It is easy to understand that, when a container is provided with a pouring lip and a lateral handle, it is essential that after assembly of the metering pouring lip with the neck of the container, the pouring lip have, relative to the axis of the neck of the container, an orientation diametrically opposite that of the handle.
At present, this result is generally obtained with a machine which places the pouring lip element of the stopper by indexing, and later the second element of this stopper is placed by a machine which screws on the second element. This way of proceeding therefore requires that these stoppers be delivered separately to the manufacturers who package the products in containers and that, further, these manufacturers have, in addition to machines for screwing the closing elements on the threaded necks of the containers, machines for placing pouring lip elements exhibiting indexing means specific to the stoppers and containers considered. Placing of these stoppers therefore requires the performance of two successive operations, namely, placing of the pouring lip element with indexing, followed by placing the closing element by screwing.